M4T28-BR12SH1 CONTAINS LITHIUM CELL
M4T28-BR12SH1 CONTAINS LITHIUM CELL – STMicroelectronics SNAPHAT® Battery & Crystal Module
The M4T28-BR12SH1 CONTAINS LITHIUM CELL module (manufactured by STMicroelectronics) is a detachable, top-mounted SNAPHAT® power source and 32.768 kHz quartz crystal combination. Designed specifically to mate with ST’s non-volatile TIMEKEEPER® Real-Time Clock (RTC) ICs and supervisory circuits in 28-pin and 44-pin SOIC packages, this unit provides uninterrupted backup power to retain system time, date, and SRAM data during system power outages.
The two-piece SNAPHAT® architecture solves a critical manufacturing challenge: it allows the underlying SOIC integrated circuit to undergo standard high-temperature surface-mount reflow soldering without exposing the heat-sensitive lithium coin cell or tuning-fork crystal to thermal damage. Once reflow soldering is complete, the M4T28-BR12SH1 CONTAINS LITHIUM CELL module simply snaps onto the mounted IC socket pins.
As printed on the bright yellow protective housing in the product image, the device clearly displays its ST logo, series name (TIMEKEEPER® SNAPHAT®), part number (M4T28-BR12SH1), UL recognition mark, and regulatory warning: M4T28-BR12SH1 CONTAINS LITHIUM CELL.
Key Features of the M4T28-BR12SH1 CONTAINS LITHIUM CELL Module
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Removable SNAPHAT® Top Architecture: Snaps directly onto surface-mounted SNAPHAT SOIC bases post-reflow, protecting the lithium cell and crystal from thermal stress during automated soldering.
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Integrated Lithium & 32.768 kHz Crystal: Combines a 2.8 V Lithium Carbon Monofluoride (LiCF) coin cell (48 mAh capacity) and a precision 12.5 pF load capacitance crystal inside a single shielded top.
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High Vibration & Shock Resistance: Four molded-in retaining clips and gold-plated 4-pin sockets ensure secure mechanical locking that withstands shock levels exceeding 100 g.
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Keyed Insertion Design: Features physical keying on the socket connections to eliminate polarity errors during assembly.
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Long Shelf & Service Life: Low self-discharge rate of the LiCF chemistry ensures long-term non-volatile data retention (exceeding 10 years depending on RTC current draw).
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Environmentally Compliant & UL Recognized: Mercury-free and lead-free construction certified under UL Component Recognition programs.
Common Applications and Industrial Usage
The reliable backup capabilities and field-replaceable structure of the M4T28-BR12SH1 CONTAINS LITHIUM CELL module make it widely used across industrial, networking, and embedded electronics:
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Industrial Automation & PLCs: Supplies continuous backup power to Real-Time Clock circuits in programmable logic controllers, industrial PCs, and SCADA systems.
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Telecommunications & Networking Equipment: Preserves system logs, encryption keys, and time stamps in network routers, switches, and server motherboards during grid failures.
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Smart Utility Meters & Energy Controllers: Retains vital billing registers, event histories, and real-time clock tracking during utility power dropouts.
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Medical & Laboratory Instrumentation: Maintains calibrated real-time data logs in medical monitoring devices where timing accuracy is critical.
Technical Specifications
The core electrical, physical, and environmental parameters for the M4T28-BR12SH1 CONTAINS LITHIUM CELL module are detailed below:
| Parameter Specification | Technical Details & Operational Values |
| Component Classification | Detachable SNAPHAT® Battery & Crystal Module |
| Primary Target Keyword | M4T28-BR12SH1 CONTAINS LITHIUM CELL |
| Manufacturer / Family | STMicroelectronics / TIMEKEEPER® SNAPHAT® |
| Commercial Reference | M4T28-BR12SH1 |
| Battery Chemistry | Lithium Carbon Monofluoride (LiCF) |
| Nominal Voltage / Capacity | 2.8 VÂ / 48 mAh |
| Crystal Frequency / Load Cap. | 32.768 kHz / 12.5 pF (pm 35 ppm accuracy @ 25°C) |
| Pin Count / Interface Style | 4 Gold-Plated Socket Pins (Horizontal Mounting) |
| Mating SOIC Packages | ST 28-pin and 44-pin SNAPHAT® SOIC bases |
| Operating Ambient Temp (T_A) | 0°C to +70°C (Grade 1) |
| Storage Temperature (T_STG) | -40°C to +85°C |
| Package Dimensions (L x W x H) | 21.08 mm x 14.22 mm x 6.48 mm |
| Weight / MSL Rating | Approx. 2.2 g / MSL 1 (Unlimited) |
Handling Guidelines and Best Practices
IMPORTANT WARNING: Because the M4T28-BR12SH1 CONTAINS LITHIUM CELL, do not subject the module to soldering wave ovens, reflow profiles, or temperatures exceeding 85°C.
Post-Reflow Assembly: Always mount the underlying TIMEKEEPER® SOIC IC onto the PCB first via standard SMT processes. Press the M4T28-BR12SH1 CONTAINS LITHIUM CELL top onto the mounted SOIC socket pins after the board has cooled down.
Field Replacement: To replace a depleted battery in the field, insert a small flat-head screwdriver or SNAPHAT extraction tool under the retaining clips to pop off the old module without desoldering the main IC.
To review official international safety standards for information technology equipment and lithium battery component usage, consult the IEC 60950-1 Information Technology Equipment Standard Directory.
To check real-time regional warehouse inventory or submit request-for-quote forms for bulk component supply, please contact our sales engineers via the Control Qatar Contact Page.
